1. Field of Invention
The present invention relates generally to the field of load handling methods and apparatus, and more particularly to a hook assembly and method for extending the reach of load handling systems presently known in the art.
While the present invention is subject to a wide range of load handling applications, it is particularly well suited for extending the reach of load handling equipment and other devices used to insert and remove palletized loads into and out of International Standards Organization (ISO) containers.
2. Technical Background
ISO containers have long been a standard vehicle for transporting equipment and other goods via air, land, sea, and rail. These containers are durable, rugged in construction, and are sized and shaped such that they are readily and economically securable to rail cars, trucks, ship holds, and cargo bay floors of large aircraft. Sufficiently bracing loads within these containers, however, has proved to be a challenging task.
In view of these load bracing issues, the United States Armed Services is moving toward the employment of a Container Roll-in/out Platform (CROP) as the load/unload platform for equipment and other goods carried in ISO containers The M3 and M3A1 CROP each has a flat cargo body with a folding front end structure assembly designed for use with the Palletized Load System (PLS) truck and trailer. Each is designed to be loaded onto the PLS truck and trailer and into an ISO container using the Load Handling System (LHS). Each is also capable, however, of being transported by other modes of transportation through the supply distribution system in a stand-alone configuration.
A standard M3 CROP weighs approximately 3,800 pounds, while a standard M3A1 CROP weighs approximately 4,000 pounds. The M3 CROP and the M3A1 CROP will accommodate payloads of approximately 32,450 pounds and 32,250 pounds, respectively, when loaded in an ISO container or on a PLS truck or trailer. Thus, although the CROPs are constructed largely of galvanized steel, standard loads for shipment in ISO containers typically cause some amount of bending or sagging in the CROP body or frame. Oftentimes, this bending brings the CROP frame into contact with the bottom of the ISO container. Thus, even though the CROP is typically equipped with rollers for facilitating insertion of the CROP into the ISO container, the frame to bottom contact produces frictional resistance which impedes the insertion of the CROP into the ISO container. The frictional resistance, among other things, acting against the loading force applied to the A-frame by the PLS truck often results in deflection of the A-frame during insertion of the CROP into the ISO container. While this does not generally inhibit CROP insertion at the commencement of CROP onloading, it does pose a problem as the loading process nears completion.
When the A-frame deflection is significant, it has been found that the PLS truck hook arm commonly used to insert the CROP into an ISO container is inadequate to facilitate complete insertion of the CROP into the ISO container. In addition, it has also been determined that the PLS hook arm is often not capable of reaching the A-frame of a CROP that is fully inserted within an ISO container. Generally speaking, the straight portion of the hook arm assembly often strikes the top wall of the ISO container before the CROP is fully inserted, thus inhibiting further insertion of the CROPs or before the hook arm assembly reaches the A-frame of a fully inserted CROP. In such instances, it is often necessary to enlist the aid of other vehicles, such as forklifts to complete CROP insertion or to facilitate CROP removal.
Unfortunately, the use of additional vehicles and manpower is both inefficient and economically costly. Moreover, for many operations, particularly military operations, the use of additional vehicles is impractical. The military relies heavily on the use of ISO containers for shipments to and from forward areas of operation. In many of these forward areas, forklifts and other vehicles simply are not available.
Another shortcoming also relates to deflection of the A-frame. During offloading of the CROP from an ISO container, the heavy loads can cause the A-frame to bend in the direction of the PLS truck as the PLS truck is withdrawing the CROP from the ISO container. As a result, the bail bar attached to the A-frame and grasped by the hook portion of the PLS truck hook arm may slip from the hook resulting in hook disengagement Such unexpected disengagements can cause damage to the hook, the bail bar, the A-frame, and the CROP. In addition, unexpected disengagements often lead to hazardous conditions in the loading area. Unexpected disengagements typically result in the PLS truck lunging forward, which poses a hazard for personnel in the immediate vicinity of the truck.
In view of the foregoing there is a need for an apparatus and method for extending the reach of devices used to insert CROPs into ISO containers and to remove fully loaded CROPs from ISO containers. In addition, there is a need for an apparatus and method that mounts securely to existing equipment such as PLS truck hook arms, and that can securely grasp the bail bar of CROP A-frames to prevent unanticipated disengagements. Such a device should be simple to use, inexpensive to manufacture and maintain, and readily attachable and detachable from existing equipment. It is to the provision of such a device and method that the present invention is primarily directed.